Methods And Systems For Producing Hydrogen And Capturing Carbon Dioxide

Abstract

Methods and systems for producing hydrogen and capturing carbon dioxide are disclosed. In some embodiments, the methods include the following: mixing magnesium bearing minerals with one or more acids and/or chelating agents to form a magnesium-rich solvent including magnesium hydroxide; mixing a gas including carbon dioxide with the magnesium-rich solvent in a reactor possibly in the presence of one or more water-gas shift catalysts; increasing a temperature and a steam pressure inside the reactor until a substantial portion of the magnesium hydroxide in the solvent and the carbon dioxide and water in the gas react to form magnesium carbonate and hydrogen; and increasing pH in the reactor thereby increasing a rate that the solvent and the carbon dioxide react.

What is claimed is: 
     
         1 . A method of producing hydrogen and capturing carbon dioxide, said method comprising:
 mixing magnesium bearing minerals with at least one of one or more acids and chelating agents to form a magnesium-rich solvent including magnesium hydroxide;   mixing a gas including carbon dioxide with said magnesium-rich solvent in a reactor; and   increasing a temperature and a steam pressure inside said reactor until a substantial portion of said magnesium hydroxide in said solvent and said carbon dioxide in said gas react to form magnesium carbonate and hydrogen.   
     
     
         2 . The method according to  claim 1 , further comprising:
 collecting and storing said hydrogen.   
     
     
         3 . The method according to  claim 1 , further comprising:
 adding catalysts to said reactor to facilitate the formation of hydrogen.   
     
     
         4 . The method according to  claim 3 , wherein said catalysts include at least one of magnetite, copper, or other commercially available water-gas shift catalysts, and a combination thereof. 
     
     
         5 . The method according to  claim 1 , wherein said one or more acids and chelating agents include at least one of ethylenediaminetetraacetic acid (EDTA), acetic acid, ascorbic acid, orthophosphoric acid, oxalic acid, chelating agents including catechol, guanidine, imidazole, histidine, and arginine, and a combination thereof. 
     
     
         6 . The method according to  claim 1 , further comprising:
 increasing pH in said reactor thereby increasing a rate that said solvent and said carbon dioxide react.   
     
     
         7 . The method according to  claim 1 , wherein said gas is one of a syngas produced from the gasification of a carbonaceous fuel or solid wastes, a flue gas produced from combusting a carbonaceous fuel or solid wastes, and a combination thereof. 
     
     
         8 . The method according to  claim 1 , wherein said temperature in said reactor is limited to about a calcination temperature of magnesium carbonate considering said steam pressure in said reactor. 
     
     
         9 . The method according to  claim 8 , wherein said temperature is about 200 to about 500 degrees Celsius. 
     
     
         10 . The method according to  claim 8 , wherein said steam pressure in said reactor is about 100 to about 1000 pounds per square inch. 
     
     
         11 . A system for producing hydrogen and capturing carbon dioxide, said system comprising:
 a dissolution reactor for mixing magnesium bearing minerals with at least one of one or more acids and chelating agents to form a magnesium-rich solvent including magnesium hydroxide;   a carbonation reactor in fluid communication with said dissolution reactor, said carbonation reactor being configured for reacting a gas including carbon dioxide with said magnesium-rich solvent to form magnesium carbonate and hydrogen in the presence of one or more catalysts;   a heat source in fluid communication with said dissolution reactor and said carbonation reactor, said heat source being configured to heat said carbonation reactor thereby increasing a temperature inside said reactor;   a steam source in fluid communication with said carbonation reactor, said steam source being configured to inject a steam into said carbonation reactor thereby increasing a steam pressure inside said carbonation reactor; and   a control module for controlling said heat source and said steam source;   wherein said carbonation reactor is configured to withstand an increase in said temperature and said steam pressure inside said reactor until a substantial portion of said magnesium hydroxide in said solvent and said carbon dioxide in said gas react to form magnesium carbonate and hydrogen.   
     
     
         12 . The system according to  claim 11 , wherein said catalysts include at least one of magnetite, copper, or other commercially available water-gas shift catalysts, and a combination thereof. 
     
     
         13 . The system according to  claim 11 , wherein said one or more acids and or chelating agents include at least one of ethylenediaminetetraacetic acid (EDTA), acetic acid, ascorbic acid, orthophosphoric acid, oxalic acid, chelating agents including catechol, guanidine, imidazole, histidine, and arginine, and a combination thereof. 
     
     
         14 . The system according to  claim 11 , further comprising:
 a pH control module in fluid communication with said carbonation reactor, said pH control module including a supply of basic material for increasing pH in said carbonation reactor thereby increasing a rate that said solvent and said carbon dioxide react; and   a hydrogen collection and storage module for collecting and storing hydrogen produced in said carbonation reactor.   
     
     
         15 . The system according to  claim 11 , wherein said temperature in said carbonation reactor is limited to about a calcination temperature of magnesium carbonate considering said steam pressure in said reactor. 
     
     
         16 . The system according to  claim 15 , wherein said temperature is about 200 to about 500 degrees Celsius. 
     
     
         17 . The system according to  claim 15 , wherein said steam pressure in said carbonation reactor is about 100 to about 1000 pounds per square inch. 
     
     
         18 . A method of producing hydrogen and capturing carbon dioxide, said method comprising:
 mixing magnesium bearing minerals with at least one of one or more acids and chelating agents to form a magnesium-rich solvent including magnesium hydroxide;   mixing a gas including carbon dioxide with said magnesium-rich solvent in a reactor in the presence of one or more catalysts;   increasing a temperature and a steam pressure inside said reactor until a substantial portion of said magnesium hydroxide in said solvent and said carbon dioxide in said gas react to form magnesium carbonate and hydrogen; and   increasing pH in said reactor thereby increasing a rate that said solvent and said carbon dioxide react.   
     
     
         19 . The method according to  claim 18 , wherein said catalysts include at least one of magnetite, copper, or other commercially available water-gas shift catalysts, and a combination thereof. 
     
     
         20 . The method according to  claim 18 , wherein said one or more acids and or chelating agents include at least one of ethylenediaminetetraacetic acid (EDTA), acetic acid, ascorbic acid, orthophosphoric acid, oxalic acid, chelating agents including catechol, guanidine, imidazole, histidine, and arginine, and a combination thereof.